1. Field of the Invention
The present invention relates to personal navigation devices (PNDs), and more particularly, to a method of determining a mode of transportation in a PND.
2. Description of the Prior Art
A number of navigation methods have been employed over the centuries by sailors desiring to go from one place to another without getting lost on the way or passing through dangerous waters. Whereas in the past, navigation was typically of interest to navigators on marine vessels, as more advanced navigation systems are developed, drivers, hikers, and tourists are rapidly adopting Global Navigation Satellite System (GNSS) technology to aid them in their travels.
One key to navigation is positioning, or the art of knowing precisely where one is at any given moment. In the past, positioning was accomplished through use of a sextant, which measures angular positions of celestial bodies relative to the horizon. Today, positioning may be accomplished with fair accuracy by GNSS receivers. Currently, only the NAVSTAR Global Positioning System (GPS) developed by the United States Department of Defense offers comprehensive positioning satellite coverage around the globe, though other systems should become operational by the year 2010.
A typical GPS receiver will include an antenna for receiving electrical signals transmitted by GPS satellites, and positioning circuitry for determining a position of the GPS receiver from the electrical signals, and generating corresponding position data. The antenna may be integrated into the GPS receiver, or may be connected externally through a wire. A GPS device, one type of personal navigation device (PND), may integrate the GPS receiver and further means for providing functions that use the position data generated by the GPS receiver. Typically, the GPS device may be a standalone mobile device, or may be integrated into an automobile as another instrument on the dashboard. The standalone mobile device may also be adapted for use in an automobile through a mount, which may be attached to the automobile through suction cups or other more permanent means.
The GPS device will typically include an internal map, which may be used in conjunction with the position data to determine where the GPS device is located on the map. Based on this information, a navigator function of the GPS device may calculate a route along known roads from the position of the GPS device to another known location. The route may then be displayed on a display of the GPS device, and instructions on upcoming maneuvers may be displayed on the GPS device and played through a speaker of the GPS device to alert the user as to which maneuvers should be taken to reach their destination. As the GPS device travels along the route, the GPS device is also able to determine speed based on how far the GPS device travels over a period of time.
The GPS device may also utilize the position data to perform queries on points of interest (POIs). Typically, the GPS device will include database query functions which may be utilized to locate POIs in local databases on the GPS device, in vendor databases, or in third party databases. Thus, for example, if the GPS device is located in Seattle, the GPS device may find POIs such as Pike Place Market and the Space Needle. If the GPS device connects to the third party database through a GPRS modem, such as a cell phone, the GPS device may find even more POIs, including businesses, hotels, and gas stations.
Given so much information accessible by the GPS device, or which the GPS device is able to calculate, many new algorithms may be developed that utilize the information in the GPS device to improve integration of the GPS device's current and future locations with map and POI databases, so as to deliver more relevant and useful information to the user about their current environment and their upcoming travel journey. However, many functionalities are as yet unexplored and unimplemented, one of which is automatic determination of mode of transportation based on the information in the GPS device.